1MICE Alain Blondel, MUTAC, FNAL 15 January 2003
MICE
International Muon Ionization Cooling Experiment
This talk:motivation and measuring technique Next talk (Paul Drumm):Beam, power sources, installation at RAL,safety.
2MICE Alain Blondel, MUTAC, FNAL 15 January 2003
-- Neutrino Factory --CERN layout
µ+ → e+ νe νµ
_
interactsgiving µ+
oscillates νe ↔ νµinteracts giving µ−
WRONG SIGN MUON
1016p/s
1.2 1014 µ/s =1.2 1021 µ/yr
3 1020 νe/yr3 1020 νµ/yr
0.9 1021 µ/yr
3MICE Alain Blondel, MUTAC, FNAL 15 January 2003
comparison of reach in the oscillations; right to left:present limit from the CHOOZ experiment, expected sensitivity from the MINOS experiment, (and CNGS expts) 0.75 MW J-Parc to super Kamiokande with an off-axis narrow-band beam, Superbeam: 4 MW CERN-SPL to a 400 kton water Cerenkov in Fréjus or J-Parc from a Neutrino Factory with 40 kton large magnetic detector. INCLUDING SYSTEMATICS
sin2θ13
0.10 10 2.50 50 130
J-Parc-SK,off axis
log scale
+CNGS
4MICE Alain Blondel, MUTAC, FNAL 15 January 2003
NUFACT R&D; Cooling
Accelerato
Accelerator acceptance R ≈ 10 cm, x’ ≈ 0.05 rad
rescaled @ 200 MeV
π and µ after focusing
z Problem: µ → Beam pipe radius of accelerator & storage ring
P⊥ or x’ and x reduction needed: COOLING
5MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Ionization Cooling : the principle
H2 rf
Liquid H2: dE/dx
RF restores only P//
Beam
sol
sol
6MICE Alain Blondel, MUTAC, FNAL 15 January 2003
MUON Yield without and with Cooling
What muon cooling buys , and costs…..
exact gain depends on relative amount of phase rotation (mono-chromatization vs cooling trade off) ‘only a factor of 3-4 in US Study II’
K. Hanke, CERN scheme
System Total
Proton Driver 184.4
Target Systems 100.8
Decay Channel 5.1
Induction Linacs 351.0
Bunching 75.5
Cooling Channel 348.7
Pre-accel. Linac 207.8
RLA 391.0
Storage Ring 118.1
Site Utilities 139.6
TOTAL 1922.0
1. Quality of cooling impacts on downstream systems (accelerator)2. Major hope for reduction in cost in better cooling…
Study II cost:
7MICE Alain Blondel, MUTAC, FNAL 15 January 2003
studyII cooling channel – many challenges:Thin H2 windows,
Clean high gradient RF (risk to boil hydrogen or dammage windows) High mag. fields
Large aperture RF pill box => Beryllium windows
8MICE Alain Blondel, MUTAC, FNAL 15 January 2003
MICE cooling channel: magnets have been reduced in size (cost saving)while keeping same aperture windows and a argon gas jacket have been added for safety.
Realism
9MICE Alain Blondel, MUTAC, FNAL 15 January 2003
COOLING RINGSTwo goals: 1) Reduce hardware expense on cooling channel
2) Combine with energy spread reduction (longitudinal and transverse cooling)potentially saving on accelerator …
major problem: Kickers
(Same problem occurs in Japanese acceleration scheme with FFAG)
same cooling components as MICE(Solenoids and LH2 windows are tilted)
10MICE Alain Blondel, MUTAC, FNAL 15 January 2003
the MICE mission
The aims of the international Muon Ionization Cooling Experiment are:
To show that it is possible to design, engineer and build a section of cooling channel capable of giving the desired performance for a Neutrino Factory;
To place it in a muon beam and measure its performance in a variety of modes of operation and beam conditions, thereby investigating the limits and practicality of cooling.
in other words:
The first challenge for MICE is to turn a new concept, which on paper surely works, into an apparatus that works in practice, supported by a community of experienced people capable of operating it, maintaining it and improving it.
The next challenge is to do this in a significant way, from the combined points of view of precision, realism and relevance.
(A muon will go more than 100 time through cooling cells, in which errors accumulate.)
11MICE Alain Blondel, MUTAC, FNAL 15 January 2003
µ
Incoming muon beam
Diffusers 1&2
Beam PIDTOF 0
CherenkovTOF 1
Trackers 1 & 2measurement of emittance in and out
Liquid Hydrogen absorbers 1,2,3
Downstreamparticle ID:
TOF 2 CherenkovCalorimeter
RF cavities 1 RF cavities 2
Spectrometer solenoid 1
Matching coils 1&2
Focus coils 1 Spectrometer solenoid 2
Coupling Coils 1&2
Focus coils 2 Focus coils 3 Matching coils 1&2
10% cooling of 200 MeV muons requires ~ 20 MV of RFsingle particle measurements =>
measurement precision can be as good as ∆ ( ε out/ε in ) = 10-3
never done before either….
12MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Quantities to be measured in a cooling experiment
equilibrium emittance
cooling effect at nominal inputemittance ~10%
curves for 23 MV, 3 full absorbers, particles on crest
13MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Quantities to be measured in a cooling experiment (ctd)
number of particles inside acceptance of subsequent accelerator(nominal is 15 mm rad)
Need to count muons coming in within an acceptance box and muons coming out.
It is difficult to count very precisely particles of a given type in a bunchand to measure emittance very precisely. => single particle experiment
14MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Emittance measurement
Each spectrometer measures 6 parameters per particle x y t x’ = dx/dz = Px/Pz y’ = dy/dz = Py/Pz t’ = dt/dz =E/Pz
Determines, for an ensemble (sample) of N particles, the moments:Averages <x> <y> etc… Second moments: variance(x) σx
2 = < x2 - <x>2 > etc… covariance(x) σxy = < x.y - <x><y> >
Covariance matrix
M = M =
σσσσσσσ
σσσσσσσσ
2't
't'y2
'y
't'x2
'x
'tt2t
'yt2y
'xt'xy'xxxtxy2x
...........................
............
............
............
2'y'xyx
D4
't'y'xytxD6
)Mdet(
)Mdet(
⊥ε==ε
=εEvaluate emittance with: CompareCompare εεinin withwith εεoutout
Getting at e.g. Getting at e.g. σσx’t’x’t’is essentially impossibleis essentially impossiblewith with multiparticlemultiparticle bunch bunch measurements measurements
15MICE Alain Blondel, MUTAC, FNAL 15 January 2003
requirements on spectrometer system:
1. must be sure particles considered are muons throughout 1.a reject incoming e, p, π
=> TOF 2 stations 10 m flight with 70 ps resolution1.b reject outgoing e => Cerenkov + Calorimeter
2. measure 6 particle parametersi.e. x,y,t, px/pz , py/pz , E/pz
3. measure widths and correlations resolution in all parameters must be better than 10% of widthat equilibrium emittance (correction less than 1%)
4. robust against noise from RF cavities
16MICE Alain Blondel, MUTAC, FNAL 15 January 2003
B
tracking in a solenoid:
SIMULATIONS:
LOI: DWARF4.0 by P.Janot: a fast simulation including dE/dx & MS (ad-hoc)
Proposal: G4MICE: Geant 4 application including everything including noise(long term FOUNDATION FOR MICE software)
17MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Pz resolution degrades at low pt :
RESULTSTRANSVERSE MOMENTUM RESOLUTION σpt = 110 keV
resolution in E/Pz is much better behaved
measurement rms is 4% of beam rms
18MICE Alain Blondel, MUTAC, FNAL 15 January 2003
measured dark currents
real background reduced by factorL/X0(H2) . L/X0(det)0.07 0.0026
Backgrounds
Dark current backgrounds measured on a 805 MHz cavity in magnetic fieldwith a 1mm scintillating fiber at d=O(1m)
Extrapolation to MICE (201 MHz):scale rates as (area.energy) X 100and apply above reduction factor 2 10-4
4 104 Hz/cm2 @ 8 MV/m @805 MHz⇒0.8 kHz/cm2 per sci-fi ⇒ 500 kHz/plane! within ± one order of magnitude !
19MICE Alain Blondel, MUTAC, FNAL 15 January 2003
.43 X 4 cells = 1.7 m ⇒ 11.5 MV for 1X 4 = 6.70 MV/m
16 MV for 2X4 = 4.65 MV/m
16 MV for 1X4 = 9.3 MV/m
=> 6.70 MV/m => 4.65 MV/m
20MICE Alain Blondel, MUTAC, FNAL 15 January 2003
concept G4MICE
background simulated at level 1000 timesthat extrapolated from measurements does NOT degrade resolution seriously(No multiplexing here!)
further improvements from the RF cavitywill be seeked (TiN coating) etc…
looks good. if this is confirmed, one could envisage running with higher gradients. This is possible if --8 MW power to one 4-cavity unit-- LN2 operation
21MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Tracker
Baseline Option:scintillating fibre tracker – 5 stations with 3 crossing double planes of 350 µm fibres readout by VLPC (High Q.E. and high gain) as in D0.
Pro: we are essentially sure that this will perform well enough for MICE. con: 43000 channels make it quite expensive (4.1 M€)
Saving alternatives: Option 1 Sci-Fi -- Reduce channel count by multiplexing channels (1/7) -- cost reduced by factor 4. -- it is not known if this can work in presence of Bkg and a few dead channels.
Option 2 Use a Helium filled TPC with GEM readout (‘TPG’) pro: very low material budget (full TPG = 2 10-4 X0) and lots of points/track (100)
cheaper (<0.5 M€ of new money) con: long integration time (50 µs vs 10 ns) => several muons at a time, integrate noise
effect of x-rays on GEMs themselves is unknown.
22MICE Alain Blondel, MUTAC, FNAL 15 January 2003
at noise rate similar to that simulated for fibers, no difficulty finding tracks and measuring them.
resolution somewhat better than sci-fi (which is good enough)
difficulty: nobody knows the effect of RF photons on the GEM themselvestests in 2003, decision October 2003
24MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Upstream Particle Identification
Even with a solenoid decay channel, the beam is not perfect. Entering electrons and protons have different cooling propertiesand must be rejected (easy)
Pions are more of a problem since they can decay in flight with a daugther of different momentum Big bias in emittance!
requires less than one permil contamination in final sample.
TOF in the beam line with 10m flight path and 70 ps resolution providesπ/µ separation better than 1% @ 300 MeV/c⇒ it is sufficient that the beam has fewer than 1 pi for 10 muons
A beam Cherenkov is foresen to complete the redundancy in this system.
25MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Downstream PID0.5% of muons decay in flight. This leads to large bias if a forward-decay electron is confusd with a muon
two systems are foreseen to eliminate electrons below 10-3 : Aerogel Cherenkov and a calorimeter.
Positive Identification of a particle in the calorimeter consistent with a muon combined with no signal in the Cherenkov
26MICE Alain Blondel, MUTAC, FNAL 15 January 2003
PRECISION
1. statistical--emittance is measured to 10-3 with ~106 muons. -- ratio of emittances to same precision requires much fewer (105)
we are using the same muons and they go through little material:statistical fluctuations largely cancel in the ratio
-- Due to RF power limitations we can run about 10-3 duty factor 1ms/s -- To avoid muon pile up we want to run at ~1 muon per ISIS bunch (1/330ns)
3000/s-- The emittance generation keeps 25% of incoming muons within acceptance -- about 1/6 are on crest => 100 good muons per second.
A 10-3 measurement of emittance ratio will take less than one hour
N.B. this assumes a beam line with a solenoid to be obtained from PSI. A quadrupole channel has more background and less rate, and would lead to a
time longer by a factor ~10.
27MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Systematics
. MICE measures e.g. (εout / εin)exp = 0.894 ± 0.001 (statistical)
compares with (εout / εin)theory. = 0.885
and tries to understand the difference.and tries to understand the difference.
SIMULATIONSIMULATION
REALITYREALITY
MEASUREMENTMEASUREMENT
A.A. theory systematics: modeling of cooling cellis not as reality
B. B. experimental systematics:modeling of spectrometers
is not as reality
MICEMICE--FICTION:FICTION:
28MICE Alain Blondel, MUTAC, FNAL 15 January 2003
The errors of class AA (Cooling Theory)must not affect the expected 10% cooling effect by more than 10–3 absolute, i.e., 1% of its value. Errors in this category include:• Uncertainties in the thickness or density of the liquid-hydrogen absorbers
and other material in the beam• Uncertainties in the value and phase of the RF fields • Uncertainties in the value of the beta function at the location of the absorbers
Misalignment of the optical elementsUncertainty in the beam energy scale
Uncertainties in the theory (M.S. and dE/dx and correlation thereof)
All errors of type A become more important near the equilibrium emittance.
The errors of class BB (Experimental): systematic differences between incoming and outgoing measurement devices.
efficiency differencesdifferent misalignments possible differences in the magnetic field.
Solutions:Step III or run MICE empty with no RF or analyse cooling vs muon phase (free)
29MICE Alain Blondel, MUTAC, FNAL 15 January 2003
3 hall probes
Positioning holes
SC Coils
Magne tic
senso rs
Magnetic measurements
design of system and procedures by Saclay (Rey, Chevallier)
NIKHEF will provide the probes (Linde)
Most critical is the control of the magnetic fields. For this reason MICE will be equipped with a set of magnetic measurement devicesthat will measure the magnetic field with a precision much better than 10–3.
30MICE Alain Blondel, MUTAC, FNAL 15 January 2003
µ- STEP I: 2004
STEP II: summer 2005
STEP III: winter 2006
STEP IV: spring 2006
STEP V: fall 2006
STEP VI:2007
31MICE Alain Blondel, MUTAC, FNAL 15 January 2003
The statistical precision will be very good and there will be many handles against systematics.
We believe that the systematic errors on the measurement of the ratio of emittances can be kept below 10-3
This will require careful integration of the acquisition of data from the spectrometers and from the cooling cell.
A lot remains to be done in this area, admittedly, to make surethat MICE has foreseen the necessary diagnostics by the time it turns on.
32MICE Alain Blondel, MUTAC, FNAL 15 January 2003
January 10 2003
Proposal to the Rutherford Appleton LaboratoryAn International Muon Ionization Cooling Experiment (MICE)
The aims of the international Muon Ionization Cooling Experiment are:
To show that it is possible to design, engineer and build a section of cooling channel capable of giving the desired performance for a Neutrino Factory;
To place it in a muon beam and measure its performance in a variety of modes of operation and beam conditions.
The MICE collaboration has designed an experiment where a section of an ionisation cooling channel is exposed to a muon beam and reduces its transverse emittance by 10% for muon momenta between 140 and 240 MeV/c. Improvements in the evaluation of the background in the detectors due to radiation from the RF cavities make us confident that the desired precision can be achieved.
A scenario exists to satisfy the safety requirements related to the use of liquid hydrogen as cooling medium.
Assuming proper funding and support, ionization cooling of muons will be demonstrated by 2007
Abstract (excerpts)
33MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Further Explorations
We have defined a baseline MICE, which will measure the basic cooling properties of the StudyII cooling channel with high precision, for a moderategradient of ~8 MV/m, with Liquid Hydrogen absorbers.
Many variants of the experiment can be tested.
1. other absorbers: Various fillings and thicknesses of LH2 can be envisagedThe bolted windows design allows different absorbers to be mounted.
2. other optics and momentum: nominal is 200 MeV/c and β = 46 cm. Exploration of low β (down to a few cm at 140 MeV/c)Exploration of momentum up to 240 MeV/c will be possible by varying the currents.
3. the focus pairs provide a field reversal in the baseline configuration, but they have been designed to operate also in no-flip mode which could have larger acceptance both transversally and in momentum (Fanchetti et al)
(We are not sure this can be done because of stray fields…)
4. Higher gradients can be achieved on the cavities, either by running themat liquid nitrogen temperature (the vessel is adequate for this) (gain 1.5-1.7)or by connecting to the 8 MW RF only one of the two 4-cavity units (gain 1.4)
34MICE Alain Blondel, MUTAC, FNAL 15 January 2003
International Muon Ionization Cooling Experiment Organization:
Steering committee: A. Blondel*1 (University of Geneva) H. Haseroth (CERN**) R. Edgecock (Rutherford Appleton Laboratory)I. Ivaniouchenkov2 (RAL) Y. Kuno (Osaka University) S. Geer (FNAL), D. Kaplan 3(Illinois Institute of Technology) M. Zisman (Lawrence Berkeley Laboratory) * convener, 1EU spokesperson, 2Interim Project Engineer, 3US spokesperson, secretary
• Conveners of technical teams: • a) Concept development: R. B. Palmer (BNL), R. Edgecock (RAL/CERN) • b) Experiment simulations: M. G. Catanesi (Bari), Y. Torun (IIT) • c) Hydrogen absorbers: S. Ishimoto (KEK) M. A. C. Cummings (Northern Illinois)• d) RF cavities, power sources: Derun Li (LBNL), R.Church (RAL), H.Haseroth (CERN)• e) Magnetic system: M. A. Green (LBNL), J.-M. Rey (CEA Saclay) • f) Particle detectors: V. Palladino (Napoli), A. Bross (FNAL) • g) Beam line: P. Drumm (RAL) • h) RF radiation: J. Norem (Argonne), E. McKigney (IC London)• i) Engineering and Integration: I. Ivaniouchenkov (RAL), E. Black (IIT)
Collaboration meetings 3X a year: US,UK,EU, etc… S.G. phone conf. every 3 weeksVideo Conferences every 3 weeks (not easy!)
35MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Participating institutes: (142 authors) Belgium: Louvain La Neuve (Ghislain Gregoire)
Netherlands: NIKHEF amsterdam (Frank Linde)
INFN: Bari (M.G.Catanesi) Frascati (Michele Castellano) Genova (Pasquale Fabbriccatore) Legnaro (Ugo Gastaldi) Milano (Maurizio Bonesini) Napoli (Giuseppe Osteria) ,Padova (Mauro Mezetto) , Roma(Ludovico Tortora), Trieste (Marco Apollonio)
France DAPNIA, CEA Saclay (Jean-Michel Rey)
Switzerland: Geneva (Alain Blondel), ETH Zürich (André Rubbia), PSI (Claude Petitjean)
UK: Brunel (Paul Keyberd), Edimburg(Akram Khan, Glasgow (Paul Soler), Rutherford Appleton Laboratory (Rob Edgecock), University of Oxford (Giles Barr),Imperial College London (Ken Long), Liverpool (John Fry), Sheffield (Chris Booth)
CERN (Helmut Haseroth)
Russia Budker Institute Novosibirsk (Sasha Skrinsky) (+ Dubna, Lebedev under discussions)
Japan KEK (Shigeru Ishimoto), Osaka University(Yoshitaka Kuno)
USA Argonne National Laboratory (Jim Norem) Brookhaven National Laboratory (Bob Palmer)Fermi National Accelerator Laboratory (Steve Geer, Alan Bross)Lawrence Berkeley National Laboratory (Michael Zisman)University of Iowa (Yasar Onel), Fairfield University (David Winn) University of California Los Angeles (David Cline)University of Mississippi (Don Summers) U.C. Riverside, (Gail Hanson) University of Chicago – Enrico Fermi Institute(Marco Oreglia) Northern Illinois University (Mary Anne Cummings)Illinois Institute of Technology (Danial Kaplan)Jefferson Lab (Bob Rimmer)
36MICE Alain Blondel, MUTAC, FNAL 15 January 2003
COST TABLE and RESPONSIBILITIES
warning: assignment of tasks will be revised when cost savings are understood (decision on tracker)
possible cost savings-- use refurbished RF from CERN: - 2500.- k€ -- use TPG or multiplex sci-fi tracker - 3000.- k€-- use HARP electronics - 500.- k€
net cost if all savings apply: 19.2net cost if all savings apply: 19.2-- M€M€ (Re: LOI 17.8 M$) (Re: LOI 17.8 M$)
40MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Future
1. Proposal sent to RAL on 10 January
2. Review panel 17 february and … mid-April
3. decision expected in spring 2003
4. funding from UK optimistic * ->
41MICE Alain Blondel, MUTAC, FNAL 15 January 2003
CLRC: (RAL)
http://www.ost.gov.uk/research/funding/budget03-06/dti-sciencebudgetbook.pdf
UK science Budget , from the departement of trade and industryoffice of science and Technology.
… … …
… … …
42MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Time Lines
Time lines for the various items of MICE have been explored – procurement delays and installation –the critical items are solenoids and RF cavities.
If funding is adequate, the following sequence of events can be envisaged * -> consistent with the logistics of the beam line upgrade at RAL and of the various shut downs.
Muon Ionization cooling will have been demonstrated ands measured precisely by
2007
At that time MINOS and CNGS will have started and mesured ∆m13
2 more preciselyJ-Parc-SK will be about to start up (Θ13) LHC will be about to start as well
It will be timely (…and not too soon!) to have by then a full design for a neutrino factory, with one of the main unknowns (practical feasibility of ionization cooling) removed.
43MICE Alain Blondel, MUTAC, FNAL 15 January 2003
µ- STEP I: 2004
STEP II: summer 2005
STEP III: winter 2006
STEP IV: spring 2006
STEP V: fall 2006
STEP VI:2007
44MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Conclusions
There is no doubt that a Neutrino Factory is the ultimate tool to study neutrino oscillations and leptonic CP violation, and a first step towards muon colliders.
Can it be done? Paper studies say Yes, but these are only paper studies… involving several new concepts, the newest being ionization cooling.
MICE aims at turning this new concept into an apparatus that works, with a community of people able to operate it, maintain it, improve it.
The MICE collaboration, supported by the enthusastic UK community, has designed an experiment based on a full cell of studyII and a set of spectrometers to measure the emittance reduction of 10% with a precision of 10-3. It will also be capable of exploring a number of beam and optics conditions beyond the baseline.
The collaboration has organised responsibilities, and determined the costs and time line of the experiment. The crucial safety issues have been addressed and a solution is proposed that should be adequate.
If all goes well ionization cooling will have been demonstrated in 2007. This is very timely and …… not too soon!
45MICE Alain Blondel, MUTAC, FNAL 15 January 2003
Site Proposed for MICE Plant
Proposed route for services
Alternative route for services
Proposed site for controls & control room (presently the cable store and under the ISIS control room).
Proposed new linac cooling plant room
47MICE Alain Blondel, MUTAC, FNAL 15 January 2003
1541 1541 3333
428 108
644 1972
1785
841821
428
108
644
1972
1785
84
1821
187 1616
Volume in blue: 1 kGauss field
Volume in orange: 5 Gauss field
48MICE Alain Blondel, MUTAC, FNAL 15 January 2003
µ-beam
Detector 1 Absorber 1 Detector 2Absorber 2 Absorber 3 RF 1 RF 2
µ-beam
Detector 1 Absorber 1 Detector 2Absorber 2 Absorber 3 RF 1 RF 2
Vacuum LH2 He Detector gasput an argon jacket around the experimentwill ensure max., safety and minimum multiple scattering.
still to pass the safety review!
liquid hydrogen safety: liquid hydrogen must not come into contact with either oxygen or an ignition source. Major risk involved in the cryo-pumping of air/O2 on the cold surfaces in case of a small leak. This must be shielded against. …. without increasing the amount of multiple scatterng too much!